Air detector for webs



Oct. 15, 1968 J LUCKETT 3,405,552

AIR DETECTOR FOR WEBS 'Filed March 29, 1966 II. III!!! INVENTOR THOMASJ. LUCKETT w i fiw, a

T'TORNEYS United States Patent 3,405,552 7 AIR DETECTOR FOR WEBS ThomasJ. Luckett, Suitland, Md. (7901 Pennsylvania Ave. SE, Washington, 11C.20028) Filed Mar. 29, 1966, Ser. No. 538,367 7 Claims. (Cl. 7337.7)

ABSTRACT OF THE DISCLOSURE This disclosure has to do with a detectorparticularly adapted for use in an atmosphere laden with dust and otherminute foreign matter, including printing material mist and wherein thedetector is particularly adapted for detecting ruptures and voids in amoving web. The detector includes a bracket having means for mountingthe same on a web supporting apparatus and includes a fluid nozzle to bedisposed on one side of a web and a direct action control memberhingedly carried by the bracket on the opposite side of a web and havinga reaction portion in opposite alignment with the fluid nozzle fordirect actuation of the control member by fluid from the fluid nozzleonly in the absence of an intermediate web portion.

This invention relates in general to new and useful improvements indetectors for webs, and more particularly to an air detector for paperwebs.

This invention particularly relates to detectors to be utilized inconjunction with machinery having webs travelling at high speedstherethrough. Such machinery includes printing presses. In the past bothmechanical and electronic detectors have been utilized. The electronicdetectors have been in the form of electric eyes and while electric eyesare known to perform satisfactory in many environments, the dust passingoff of the fast travelling paper webs, as well as ink mist, frequentlycoated the light lens so as to render the electric eyes ineffective.While the paper dust and ink mist did not present a material problemwith respect to conventional mechanical detectors of the type which rideon the web, the mechanical detectors in use prior to this invention hada more material deficiency. When the paper web had a defect therein,such as a slime hole or a slight rip, the mechanical detectors woulddrop into the opening in the paper while detecting the defect and tearthe paper out of the mechanism while shutting the mechanism down.

In accordance with this invention, a detector which is suitable for usein conjunction with a paper web and under conditions of paper dust andink mist has been provided, the detector being of the mechanical typebut being of a construction wherein direct contact with the web iseliminated at all times.

Another object of this invention is to provide a novel detector whichutilizes an air stream which is directed against the moving web andwhich has associated therewith a lever which is normally unaffected bythe air stream, but which is tripped should the web have an openingtherein through which the air stream may pass.

Another object of this invention is to provide a novel detector whichutilizes an air stream, the detector being particularly advantageous foruse in conjunction with a moving paper web in that it is self-cleaning.

Another object of this invention is to provide a novel detector whichmay be readily incorporated in a printing press apparatus for detectingthe defects in webs, the detector being of a simple construction so asto be inexpensive and being readily mountable on existing pressstructure.

Another object of this invention is to provide a novel air detector formoving paper webs of a printing press, the detector being of aconstruction wherein the opera- 3,405,552 Patented Oct. 15, 1968 tionthereof is positive and at the same time contact with the web iscompletely eliminated.

A further object of this invention is to provide an air detector fordetecting defects in a rapidly moving paper web moving through aprinting press and wherein the detector is of a construction so as to beprotected when unintentionally engaged by the moving web should ruptureof the web occur in the vicinity of the detector.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a schematic perspective view of a detector formed inaccordance with this invention and shows the relationship thereof withrespect to a moving web;

FIGURE 2 is a schematic perspective view similar to FIGURE 1 and showsthe detector detecting a rupture in the web.

FIGURE 3 is a perspective view of the detector mounted on a support barof a printing press;

FIGURE 4 is a transverse vertical sectional view taken along the line 44of FIGURE 3 and shows a web positioned within the detector;

FIGURE 5 is a vertical sectional view taken along the line 5-5 of FIGURE4.

FIGURE 6 is a horizontal sectional view taken along the line 6-6 ofFIGURE 5.

FIGURE 7 is a fragmentary perspective view of the detector having amodified form of air control.

Referring now to the drawing in detail, it will be seen that there isillustrated in FIGURE 3 a typical installation of the detector which isthe subject of this invention, the detector being generally referred toby the numeral 10. The detector 10 includes a mounting bracket 11 whichis formed of an elongated horizontal arm 12 and a depending vertical arm13. The connection between the arms 12 and 13 is reinforced so as toretain the angular relationship of these arms. The horizontal arm 12 isprovided with suitable hangers 14 for detachably suspending the detector10 from a frame member of an apparatus through which a running webpasses, the frame member 15 being a conventional member of suchapparatus including printing presses.

A tubular housing 16 extends from the lower end of the vertical arm 13in underlying relation to the horizontal arm 12. The housing 16terminates remote from the vertical arm 13 in an upwardly openingextension 17.

Referring now to FIGURE 5 in particular, it will be seen that thehorizontal arm 12 is of a two-piece construction and includes a lowerportion 18 and an upper portion 19. The hangers 14 are preferablycarried by the upper portion 19. Also, it is to be noted that the upperportion 19 has formed in the underside thereof a passage 20. The passage20 terminates at one end in alignment with an inlet passage 21 formed inthe lower portion 18 of the horizontal arm 12 at the connection thereofwith the vertical arm 13. A discharge passage or nozzle 22 is formed inthe lower portion 18 remote from the vertical arm 13. It is to 'be notedthat the discharge passage or nozzle 22 is aligned with the housingextension 17.

The housing 16 has mounted therein adjacent the vertical arm 13 anelectric control switch 23 which may be in the form of a conventionalmicroswitch. The switch 23 has a control element 24 which is depressibleto change the electrical connection of the switch 23. There is alsomounted within the housing 16 a switch control member which is generallyreferred to by the numeral 25. The switch control member 25 includes anelongated arm or lever 26 which is hingedly mounted at the end thereofdisposed adjacent the vertical arm 13 by means of a hinge 28. Theopposite end of the arm or lever 26 carries a reaction member 27 whichis seated within the housing extension 17 in alignment with the nozzle22. It is to be noted that the reaction member 27 is of a concaveconstruction so as to absorb a maximum of the force of the air streampassing out from the nozzle 22.

The vertical arm 13 has mounted thereon an air control valve 29 whichmay be of any conventional type. The air control valve 29 includes aninlet fitting 30 and a discharge fitting 31, the discharge fitting 31being coupled into the vertical arm 13 in communication with the inletpassage 21. The preferred form of air control valve 29 is solenoidoperated and includes a solenoid actuator 32 which is suitably connectedto the valve element 33 thereof.

Referring now to FIGURES l and 2 in particular, it will be seen that thesolenoid control element 32 may be connected in series with theelectrical circuit for the particular apparatus through which a web ispassing and which web is to be detected. The electrical control circuitwill include the usual start-stop switch 43 and the switch 23 isconnected in series with the switch 43 and the solenoid 32.

At this time it is pointed out that the movement of a web, such as theweb 34, through an apparatus is controlled by a plurality of rolls 35. Amajority of these rolls are driven so as to effect the movement of theweb 34.

The web 34 will have numerous defects which are undesirable and whichmust be detected. When these defects are detected, it is desirable thatthe apparatus such as a printing press, be shut down and the detectivesection of the web removed. It is also highly desirable to immediatelyshut down the apparatus in the event there should be a complete ruptureof the web.

In the normal operation of the detector 10, the rapidly moving web 13passes between the horizontal arm 12 and the housing 16. The solenoid 32is retained in a position holding the valve element 33 in the flowposition of the valve 29 so that air passes through the arm 12 and outthrough the nozzle 22 in the form of a jet. The air jet is directedagainst the web 34 and is deflected thereby so as to have no effectwhatsoever on the control member 25 or the normally closed switch 23.However, when there is an opening in the web 34, or the web 34 issuddenly ruptured, the web 34 will fail to deflect the air jet from thenozzle 32, and this air jet will impinge upon the reaction member 27, soas to move the control member 25 away from the horizontal arm 12 and toopen the switch 23. When the switch 23 is opened, the apparatus isimmediately shut down. At the same time, the circuit to the solenoid 32will be opened and the valve element 33 will be returned to its closedposition, thereby shutting off the supply of air to the nozzle 22.

The advantages of the detector as compared to mechanical detectors whichengage the rapidly moving web and the more expensive photoelectricdetectors will be apparent. A further advantage is that most webhandling equipment has associated therewith a supply of compressed air,thereby eliminating the necessity of providing a separate air source forthe detector. Inasmuch as the detector may be conveniently mounted onexisting supports of the apparatus, the cost of installing the detectorsis held to a minimum.

Another advantage of the detector 10 is that it is self-cleaning. It isquite apparent that the nozzle 22 cannot clog in that air constantlyflows therethrough during the movement of the web 34. In a like manner,the paper dust and ink mist will have no direct effect on the operationof the detector 10. The slight amount of dust or ink mist which maysettle on the reaction member 27 will not be sufiicient to trip theswitch 23. Furthermore, the detector 10 is self-cleaning in that when abreak or opening in the web 34 occurs, the air jet will impinge againstthe reaction member 27 and clean the same. Furthermore, certain of theair will pass around the reaction member 27 and enter into the housingextension 17 to effect the cleaning thereof. To facilitate cleaning ofthe housing extension 17, slots 36 are formed in the lower portions ofthe vertical walls adjacent the base of the tubular member 16.

Although a convenient source of compressed air is usually available,when it is desired to eliminate a central source of compressed air forone reason or another, including the desire to eliminate piping, thedetector may be self-contained. "In FIGURE 7, the detector 10 isillustrated as having the valve 29 omitted and there being provided inlieu thereof a small blower 37 which is driven by a wheel 38 which is,in turn, driven from the roller 35. If desired, means may be providedfor vertically adjusting the wheel 38 so as to disengage from the roller35 and thus render the detector 10 ineffective.

Although the detectors have been shown in horizontal positions with thebracket 11 disposed uppermost, it is to be understood that the detectorsmay operate under varied conditions of orientation. Also, it is pointedout here that under certain circumstances the switch 23 may be desiredto be of the normally opened type and is closed by the movement of thecontrol member 25 so as to complete a circuit to a machinery controllingrelay (not shown). In view of the fact that the orientation of thedetector 10 may vary, various arrangements of mounting of the detectorhave not been illustrated.

Although only two preferred embodiments of the invention have beenspecifically illustrated and described herein, it is to be understoodthat minor variations may be made in the detector without departing fromthe spirit and scope of the invention, as defined in the appendedclaims.

I claim:

1. A detector particularly adapted for detecting ruptures and voids in amoving web, said detector comprising a bracket having means for mountingthe same on a web supporting apparatus, a fluid nozzle carried by saidbracket, a direct action control member hingedly carried by said bracketand having a reaction portion in opposed alignment with said nozzle fordirect actuation of said control member by fluid from said nozzle onlyin the absence of an intermediate web portion, and a control elementconnected to said control member for actuation thereby, said detectorbeing particularly adapted for use in an atmosphere laden with dust andother minute foreign matter and including a protective housing for saidcontrol member and said control element.

2. The detector of claim 1 wherein said detector is particularly adaptedfor use in conjunction with a paper web passing through a printingapparatus and wherein said laden atmosphere includes paper dust andprinting material mist, said bracket having means for connecting saidfluid nozzle to a pressurized air source, and control means operable inresponse to the operation of an associated printing apparatus forassuring a continuous supply of air through said fluid nozzle during theoperation of an associated printing apparatus whereby said detector isself cleaning.

3. A detector particularly adapted for detecting ruptures and voids in amoving web, said detector comprising a bracket having means for mountingthe same on a web supporting apparatus, a fluid nozzle carried by saidbracket, a control member hingedly carried by said bracket and having areaction portion in opposed alignment with said nozzle, and a controlelement connected to said control member for actuation thereby, saidreaction portion being of a concave shape to assure a maximum reactionfrom fluid under pressure from said nozzle.

4. A detector particularly adapted for detecting ruptures and voids in amoving web, said detector comprising a bracket having means for mountingthe same on a web supporting apparatus, a fluid nozzle carried by saidbracket, 21 control member hingedly carried by said bracket and having areaction portion in opposed alignment with said nozzle, and a controlelement connected to said control member for actuation thereby, saidbracket having means for connecting said fluid nozzle to a pressurizedair source including a self-contained air pump having means for drivenengagement with a web supporting roll.

5. The detector of claim 1 wherein said bracket is generally L-shapedand includes first and second arms, said housing being carried by saidsecond arm and extending in generally spaced parallel relation to saidfirst arm, and said second arm having means for connecting said fluidnozzle to a pressurized fluid source.

6. The detector of claim 1 wherein said housing has an extensionreceiving said reaction portion, and said housing extension openstowards said fluid nozzle.

7. The detector of claim 6 wherein said housing extension isself-cleaning by fluid from said fluid nozzle and has fluid escapeopenings below said reaction portion.

References Cited UNITED STATES PATENTS 2,900,468 8/1959 Joy. 3,188,8566/1965 Schneider 7337.7

FOREIGN PATENTS 442,365 2/ 1936 Great Britain.

DAVID SCHONBERG, Primary Examiner.

WILLIAM HENRY II, Assistant Examiner.

